I've been to the one in Nashville and it's amazing! The ice slides are a lot of fun - be sure to do them even if you are an adult.
The only bad thing is the price -
it's around $17 per person here.
I get in free because I have a friend that works it every year. I'm not sure if I would do it if I had to pay, but I love walking around Gaylord Opryland at Christmas, so it's a great evening out.
If the price doesn't bother you, I'd say go for it.
If it's the same size as the one in Nashville, as long as it's not crowded, I'd say it'd take about an hour to just soak up the atmosphere.
Remember to bring gloves and a scarf though.
The parka they give you keeps you warm, but your hands and nose start to suffer after awhile.
The pictures turn out really well.